Publications (university bibliography)

Anzahl der Treffer: 265
Erstellt: Tue, 16 Jul 2024 23:03:04 +0200 in 0.0663 sec


Hamouda, Noureddine; Babes, Badreddine; Boutaghane, Amar; Gensior, Albrecht; Rädel, Uwe
Enhancing the width of molten pool and the tracking of welding current in gas metal arc welding processes using a robust PIλDμ controller. - In: Proceedings of the 2022 International Conference of Advanced Technology in Electronic and Electrical Engineering (ICATEEE), (2022), insges. 6 S.

With a high-speed welding power source based on better performance power electronic components and modern control methods, self-regulation of the electrode contact-tube to work-piece distance may be provided to offer With a high-speed welding power source based on better performance power electronic components and modern control methods, self-regulation of the electrode contact-tube to work-piece distance may be provided to offer additional features that can be fine-tuned to automate and improve the gas metal arc welding (GMAW) process. In this article, the dynamic properties of a self-regulated electrode to workpiece have been investigated when the length between the torch and the workpiece changes over time. The significant parts of arc welding processes have been analyzed and the suggested fractional PID (PI λ D μ ) regulator has been created to keep the welding current during the fusing and short-circuiting of electric wires within a specified range. In this study, the most effective FOPID regulator parameters is designed with a weighted sum multi-objective optimization technique using the Bacterial Foraging Optimization (BFO) technique with weights associated with various criteria including Integral Absolute Error (IAE), Integral Time Absolute Error (ITAE), Integral Time Square Error (ITSE), and Integral Square Error (ISE). Numerical simulations using MATLAB/SIMULINK are conducted to indicate the usefulness of the proposed P Iλ D μ controller over conventional PID controller and knowledge of the processes, which adjust the welding voltage and arc current in reaction to variations in arc length. The simulation results show that this automatic arc welding control system can perform effectively.



https://doi.org/10.1109/ICATEEE57445.2022.10093761
Seifert, Florian;
Wirkungen von Entladungen auf dielektrische Grenzflächen bei Gleichspannung und überlagerter mittelfrequenter Wechselspannung. - Ilmenau : Universitätsbibliothek, 2022. - 1 Online-Ressource (iv, 127 Seiten)
Technische Universität Ilmenau, Dissertation 2022

Mit der Energiewende und der damit verbundenen verstärkten Nutzung von regenerativen Energien und effizienten Energieversorgungssystemen nimmt die Anwendung der Gleichstromtechnik stark zu. Zur Anbindung erneuerbarer Energieanlagen und Kopplung zwischen Gleichspannungsnetzen werden leistungselektronische Stromrichter genutzt. Die Schaltfrequenzen leistungselektronischer Topologien reichen in der Regel bis zu 100 kHz (Mittelfrequenz). Dadurch können Spannungen auftreten, die einen unterlagerten Gleichspannungsanteil und einen überlagerten Wechselspannungsanteil aufweisen. Diese Spannungsform wird als Mischspannung bezeichnet. Für die wissenschaftlichen Untersuchungen wird eine sinusförmige mittelfrequente Wechselspannung einer Gleichspannung überlagert. Entladungen an dielektrischen Grenzflächen von Isoliersystemen bei dieser Mischspannungsform besitzen ein großes Zerstörungspotential. Sie sind Untersuchungsgegenstand dieser Arbeit. Es werden verschiedene Wirkungen von Entladungen an der dielektrischen Grenzfläche zwischen Luft und Polyethylen bei Mischspannung untersucht. Dabei wird die elektrische Durchschlagfestigkeit der dielektrischen Grenzfläche beim Auftreten von Teilentladungen (direkte Wirkung) und die Aufladung der dielektrischen Grenzfläche durch Teilentladungen (indirekte Wirkung), die zu einer erhöhten elektrischen Feldbeanspruchung führt, bei Mischspannung bestimmt. Es zeigt sich der wesentliche thermisch-erosive Einfluss von Teilentladungen bei mittelfrequenter Spannung auf den Durchschlagsprozess eines Isoliersystems. Anhand der Entladungseinsetzspannung und der Entladungsanzahl bei Mischspannung wird das Zerstörungspotential aufgezeigt. Außerdem wird die Aufladung der dielektrischen Grenzfläche durch die bei den Entladungsvorgängen gebildeten Raumladungen bei Mischspannung gemessen. Die Änderung der elektrischen Feldstärke durch den Aufbau der Raumladungen beeinflusst die Entstehung von Entladungsprozessen und die Aufladung der dielektrischen Grenzfläche erheblich. Die Erkenntnisse der Aufladungsmessung werden durch Plasma-Simulationen mittels Finite-Elemente-Methode unterstützt. Diese Dissertation liefert somit wichtige Erkenntnisse zu den relevanten Wirkungen von Entladungen auf dielektrische Grenzflächen bei mittelfrequenten Mischspannungen. Die Kenntnis dieser Wirkungen können als Basis für Alterungsuntersuchungen genutzt werden.



https://doi.org/10.22032/dbt.55251
Cai, Hui; Song, Xinya; Jiang, Teng; Rädel, Uwe; Schlegel, Steffen; Westermann, Dirk
Reinforcement learning-assisted controller parameterization based on improving oscillatory stability in converter-dominant power system. - In: 2022 IEEE PES Innovative Smart Grid Technologies Conference Europe (ISGT-Europe), (2022), insges. 5 S.

Due to the cascade control loop in the single converter and interactions among converters, the converter-based system is more likely to become unstable. The general controller parameterization methods for a converter are based on its parameters and states. Considering the possible oscillation effect from other converters nearby, a new procedure of controller parameterization with the help of reinforcement learning (RL) is then proposed. By setting an oscillatory stability indicator as a reward during the training of an RL-agent, a set of controller parameters are calculated and applied in the converter-dominant power system to improve the system oscillatory stability. To this end, an indicator that can represent the stability margin should be first selected. Afterwards, a mathematical relationship is constructed between the controller parameters, the stability indicator, and the current observed states. Experimental results are presented and compared with the standard analytical parameterization method.



https://doi.org/10.1109/ISGT-Europe54678.2022.9960583
Gensior, Albrecht;
Modellbildung und Regelung leistungselektronischer Systeme unter Verwendung nichtlinearer Entwurfsverfahren. - Düren : Shaker Verlag, 2022. - vi, 180 Seiten. - (Berichte aus der Elektrotechnik)
Technische Universität Dresden, Habilitationsschrift 2022

ISBN 978-3-8440-8858-8

Gui, Qiuye; Fehr, Hendrik; Gensior, Albrecht
Stability assessment and optimization of MMC energy balancing for drive applications at standstill using an averaging approach. - In: 2022 24th European Conference on Power Electronics and Applications (EPE'22 ECCE Europe), (2022), S. P.1-P.10

A new controller design framework for periodic systems is presented and applied to the Modular Multi-level Converter energy balancing. It provides a rigorous stability analysis for the state-of-art averaging control and the approach using constants as reference for the instantaneous energies. An optimized controller with improved performance is derived and verified by simulation and experiment.



https://ieeexplore.ieee.org/document/9907170
Xie, Jun; Henneberg, Dustin; Suberski, Martin; Ellinger, Thomas; Rädel, Uwe; Petzoldt, Jürgen
A simplified braking method for direct matrix converter-fed PMSM drives with consideration of avoiding regenerative energy. - In: 2022 24th European Conference on Power Electronics and Applications (EPE'22 ECCE Europe), (2022), S. P.1-P.8

This paper presents a simplified braking method for direct matrix converter (DMC) - fed permanent magnet synchronous motor (PMSM) drives with special consideration of avoiding the regenerative energy from feeding back to the grid. As a four-quadrant converter, the DMC has the bidirectional energy-flow capability, which is seen as a great benefit. However, the regenerative energy feeding back to the grid is not always needed, in some cases might be not allowed or not possible. These could happen due to the grid load status, strict quality specifications of the grid current or grid failure, where the DMC needs to be decoupled from the grid. In order to avoid the regenerative energy temporarily or completely, a three-phase diode bridge (B6) with chopper resistance on the motor side is employed together with the traditional B12-clamp circuit, which is used for overvoltage protection. Furthermore, the motor torque during braking could be controlled without large fluctuation and within the required limitation. The principle of the proposed strategy is described in detail. Simulation results are used to verify the feasibility of the proposed strategy.



https://ieeexplore.ieee.org/document/9907709
Fehr, Hendrik; Gensior, Albrecht; Möckel, Andreas; Atzler, Frank; Roß, Tilo; Reincke-Collon, Carsten
Feasibility assessment of variable-speed generator set concepts with focus on rating of power electronic equipment. - In: 2022 24th European Conference on Power Electronics and Applications (EPE'22 ECCE Europe), (2022), S. P.1-P.10

Mobile generator sets are mainly used for the supply of electrical power in off-grid applications, e.g. at construction sites, as well as for grid support parallel to weak grid access points. Furthermore, they are used for emergency power supply.



https://ieeexplore.ieee.org/document/9907088
Xie, Jun; Henneberg, Dustin; Suberski, Martin; Kusebauch, Manuel; Rädel, Uwe; Petzoldt, Jürgen
An optimized compensation strategy of direct matrix converter-fed PMSM drives with field weakening under unbalanced supply conditions. - In: 2022 24th European Conference on Power Electronics and Applications (EPE'22 ECCE Europe), (2022), S. P.1-P.10

This paper presents an optimized compensation strategy for direct matrix converter (DMC) - fed permanent magnet synchronous motor (PMSM) drives with special consideration of the modification in field weakening control under unbalanced supply conditions. The imbalance of input voltage conditions in a three wire system are analysed and considered to be composed of positive and negative sequence components. To determine unbalance factor of the grid and decompose the positive and negative sequence components, the dual second order generalized integrator (DSOGI) and positive sequence calculator (PSC) algorithm are introduced. In order to achieve balanced output while optimizing the input current to be sinusoidal, the modulation index based on direct modulation method and the field weakening regulator are then adjusted according to unbalance factor of the input voltage conditions. The principle of the proposed compensation strategy is explained in detail. Simulation results are used to verify this proposed strategy. A low voltage laboratory platform consisting of DMC and servo motor is implemented and controlled using hybrid hardware concept based on field-programmable gate array (FPGA) and digital signal processor (DSP). Experimental studies on the laboratory prototype confirm the feasibility and effectiveness of the proposed method.



https://ieeexplore.ieee.org/document/9907529
Gnärig, Lasse; Gensior, Albrecht; Laza, Saioa Burutxaga; Carrasco, Miguel; Reincke-Collon, Carsten
Model reduction using singular perturbation methods for a microgrid application. - In: 2022 24th European Conference on Power Electronics and Applications (EPE'22 ECCE Europe), (2022), S. P.1-P.10

The paper deals with the modeling of an island grid for the purpose of simulation. Since the behavior of the system is affected by phenomena taking influence in different time-scales, a model reduction scheme is proposed that leads to simpler models which reduce the computational burden in simulations. Compromises in the modeling procedure are addressed by investigating simulation studies.



https://ieeexplore.ieee.org/document/9907517
Wei, Jianfeng; Rädel, Uwe; Petzoldt, Jürgen
Design of LCL filter for DC converter by using analytical equations. - In: PESS 2021 - Power and Energy Student Summit, (2022), S. 46-51

This paper proposes a design method of the DC inverter LCL filter based on the buck circuit to improve the power quality. The LCL filter reduces output ripple current and ripple voltage and improves the power quality. Two design methods are given in the article. The first method is to design an LCL filter without feedback. Another way is to design an LCL filter with feedback through transfer function and Fourier transform. Finally, the influence of the LCL filter developed using two different methods on the circuit is compared and analyzed through modelling and simulation results.